\[\sqrt{\frac{x^{2} - 2x - 8}{16 - x^{2}}}\]
\[\frac{x^{2} - 2x - 8}{16 - x^{2}} \geq 0\]
\[x^{2} - 2x - 8 = (x + 2)(x - 4)\]
\[D_{1} = 1 + 8 = 9\]
\[x_{1} = 1 + 3 = 4;\]
\[x_{2} = 1 - 3 = - 2.\]
\[\frac{(x + 2)(x - 4)}{(x + 4)(x - 4)} \leq 0\]
\[\frac{x + 2}{x + 4} \leq 0;\ \ x \neq 4\]
\[- 4 < x \leq - 2.\]
\[Ответ:\ - 4 < x \leq - 2.\]